1. Technical Field of the Invention
The present invention relates to a component feeder which supplies components used for various purposes such as minute electronic components mounted on a printed circuit board by stirring and blowing the components into a component conveying path with an air blow, where the components are aligned and transferred toward a given component feeding position.
2. Description of Related Art
For mounting electronic components on a printed circuit board, a multiplicity of components need to be fed at a high speed. One of the conventional electronic component feeders which supply a great number of minute electronic components at a high speed is constructed as described below. The component feeder utilizes a tape-like component assembly comprising a tape-like member, having a multiplicity of holding recesses thereon provided in one line and opened at one side, in each of which a component is encased and closed with a cover tape. The tape-like component assembly is reeled out at a given pitch while the cover tape is peeled off to open each holding recess at a component feeding position so as to allow the component in the holding recess to be taken out by a suction nozzle.
Also known as an alternative is an even simpler method in which the components agitated by air are blown into a path where they are aligned to be fed to a given feeding position.
FIG. 1 shows a mounting apparatus A in which a component feeder B of the latter type is incorporated. The apparatus A is designed for mounting electronic components 102 onto a printed board 101. The component feeder B loaded with the electronic components 102 needed in the apparatus A is mounted on a feeder table 103 beside the mounting apparatus A. Each time it is desired to mount a given type of components, the component feeder B accommodating the desired type of components is moved to a position opposite to the mounting apparatus A.
A component 102 supplied from the component feeder B is picked up by a nozzle 105 by suction which is disposed to a mounting head 104 of the apparatus A, and placed on the a printed board 101. The printed board 101 is held on an X-Y table 106 which is adjustable along X and Y directions, so that the component 102 picked up and transferred by the nozzle 105 can be precisely mounted to a predetermined position on the board 101.
The component feeder B is constructed as described below. Components 102 are replenished into an agitation room 111 from a bulk cassette 112 which is detachably connected to the agitation room 111. The components 102 are stirred in the agitation room 111 by air supply, sent out into a component conveying path 113 which leads out of the agitation room 111. Finally, the components 102 are aligned in the component conveying path 113 and transferred by air to a component feeding position 114.
The top side of the component conveying path 113 is opened at the component feeding position 114, so that the components 102 conveyed thereto can be taken out. A shutter 115 is provided at the opened portion of the path 113. A pusher 116 is provided for pressing down a lever 117 on the component feeder B which causes the shutter 115 to open, at the time when the component 102 which has been transferred to the feeding position 114 is picked up by the nozzle 105.
One drawback of such component feeder B as described above is that there is rather little probability that the components 102 are successfully sent out from the wide agitation room 111 into the narrow component conveying path 113 in such a way that the components 102 can be aligned in one line facing to a specific direction within the component conveying path 113 by merely stirring the components in the wide agitation room 111, thus being unable to accommodate the growing needs for operating the mounting apparatus A at a higher speed in recent years.
It has been thus devised in the prior art that the air 1a is blown up obliquely toward the back side from a plurality of points at the bottom at the front and back sides in the agitation room 111 to agitate the components 102 actively, in order to prevent the narrower part of the room 111 from clogging up with the components 102 and to increase the probability of causing the components 102 to be sent into the component conveying path 113 facing to a given direction. Also, in the component conveying path 113, the air 1a is blown obliquely toward the front from a plurality of points at the bottom, so that the components 102 sent into the path 113 can be smoothly transferred to the component feeding position 114 in a line.
The opening which leads to the narrow component conveying path 113 is disposed at a lower part of a front wall of the agitation room 111 which has great width and height, where the components 102 agitated by the air la tend to accumulate, pile up one upon another, or traverse and block the opening, being a hindrance to the smooth transfer of the components 102 into the path 113 or causing the path 113 to be clogged up with the components 102.
To avoid such trouble, it has already been devised to construct the agitation room or chamber 111 to have three parts: a rear part 111a, an intermediate part 111b, and a front part 111c, the size of which reduces stepwise, from the bulk cassette 112 side toward the component conveying path 113 side, as shown in FIG. 2. Provided that the component 102 has substantially a square cross section with the equal width w and height w and a given length l (w&lt;l) as shown in FIG. 4, it is prevented that the components 102 accumulate on each other at the front wall 111d of the front part 111c of the agitation room 111 by setting the horizontal width W of the front room 111c to be w&lt;W&lt;l, as shown in FIG. 3.
If the component 102 is of a flat shape having a length l, width w and a thickness t (l&gt;w&gt;t) as shown in FIG. 13, its width being different from the thickness, the mouth of the component conveying path 113 opened in the front wall 111d of the front room 111c is set to have the width W (w&lt;W&lt;l) as mentioned above and the height T, which is determined to be t&lt;T&lt;w as shown in FIG. 5.
In such an arrangement, however, the components 102 agitated by air and accumulated around the opening at the lower part of the front wall 111d of the front part 111c tended to stand substantially at right angles with respect to the configuration of the opening of the component conveying path 113 with their widthwise or lengthwise side vertical, and in parallel to each other as shown in FIGS. 6A and 6B. There was thus still little probability of sending the components 102 in a posture as shown in FIG. 5 into the opening of the component conveying path 113, leading to the problem that the component feeder is incapable of feeding components 102 reliably and rapidly, thus being unable to accommodate a further speedup of the component mounting operation.